The present disclosure is related to printed electronic circuitry, and more specifically to a device formed by printed electronic processes in which one or more elements of the circuit are reconfigurable.
There are today a relatively large number of different techniques for producing electronic devices. One family of such techniques, of interest herein, is commonly referred to as printed electronics. Devices formed by various methods fall within the definition of printed electronics. Screen-printing, traditional and digital lithography, flexography, and jet-printing are a number of the more common of such methods. In each case, a conductive, semi-conductive or insulating material is deposited over a substrate to form interconnected passive and/or active electronic components. Printing processes typically deposit materials in the form of a solution, a slurry or in the form of a powder. Thermal and laser transfer processes may also be used to print structures. In transfer processes, a layer such as a metal film may be transferred from a carrier substrate to another substrate. Known printed electronic processes can utilize a wide variety of organic and inorganic materials for these components.
Printed electronic processes take advantage of known, relatively simple printing techniques, and are thus typically less expensive and often less environmentally hazardous than traditional lithography and deposition techniques. Certain materials and processes used for printed electronics permit printing on non-crystalline substrates, such as paper, plastic, fabric, etc. Such processes may permit printing on flexible substrates, which is not easily done with conventional electronic device fabrication techniques. Furthermore, printing processes have been developed for non-planar surfaces, which is also a challenge for conventional electronic device fabrication techniques. However, in order to maintain low cost and/or substrate flexibility, the components produced by printed electronic processes are relatively large, the circuits are relatively simple, and the circuits are fixed in terms of circuit layout and characteristics once produced.
The applications for event sensors vary widely. One exemplary application for printed electronic circuits are sensors of one form or another. An event sensor, as used herein, is a device for detecting and indicating the occurrence, duration, and/or extent of an event or a series of events. Sensed events include acceleration, changes in temperature, opening of a container or package, etc. Additional electronic circuits for amplification, processing, display, and so on are commonly used to process the sensing signals issuing from these devices.
A common requirement for many applications is very low cost. There is a further common requirement for many applications that the sensor and even the display mechanism be flexible, for example permitting it to be applied over a non-planar structure, such as a medicine bottle, shipping package, etc. Still further, in some applications it is desirable to provide a sensor without a separate voltage source (e.g., without a battery). For this reason, printed electronic circuits are well-suited for certain sensor applications. However, the circuitry for such sensor applications are of a fixed configuration, and do not permit for reconfiguration in use. Thus, these devices are fabricated for a very specific use, which must generally be understood and factored into the device design, clearly prior to use of the device in the field.